Carrying bags come in a wide variety of forms and styles. A backpack style carrying bag, commonly called a backpack, may be useful for some applications because it allows the user to distribute the weight of the bag over both shoulders and the back. Additionally, both of the user's hands may be free while carrying a backpack.
Backpacks are also found in a variety of forms. Trekking backpacks, used for hiking and camping expeditions, may include internal or external frames made of carbon fiber or aluminum, have capacities of 100 liters, include additional straps that cross the wearer's chest, waist and hips to better distribute weight and weigh 8 pounds when empty. For everyday use, a trekking backpack may be unnecessarily large and bulky and a smaller, simpler backpack may meet the user's needs. For example, for transporting a few lightweight items, cinch sacks or sack packs (which may also be referred to as drawstring backpacks) with capacities of around 8 liters and weights of just a few ounces may be sufficient. Drawstring backpacks are designed with straps that double as drawstrings to control the opening at the top of the bag. This design allows for simplicity as the assembly may require as little as a simple sack and two drawstrings resulting in relatively low manufacturing costs for the drawstring backpacks.
Due to the simplicity of sack packs and their typical use for a few lightweight items, the straps may have a tendency to slide off users' shoulders. In view of the foregoing, it would be advantageous to provide a sack pack with a device which retains the straps on the users' shoulders while maintaining the simplicity and utility of the sack pack style of backpack.